A Nowrouzi, YB Kavina, H Kochekali and RA Whitaker
A UK research team has developed a means of quantifying the performance of robot systems. Details of the design and results achieved with a PUMA 560 are described.
Mehdi Miansari, M Gorji, D. D. Ganji and Kamel Hooman
– The purpose of this paper is to improve the volume-averaged models for free convection flow in porous media.
Abstract
Purpose
The purpose of this paper is to improve the volume-averaged models for free convection flow in porous media.
Design/methodology/approach
A pore scale simulation is conducted against which an independent volume-averaged solver is fine-tuned.
Findings
Micro and macro scale results can merge if proper choice of local thermal non-equilibrium and thermal dispersion models are selected. This depends on the range of Ra values investigated.
Originality/value
This is the first time a work like this is published in the literature.
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Man has been seeking an ideal existence for a very long time. In this existence, justice, love, and peace are no longer words, but actual experiences. How ever, with the American…
Abstract
Man has been seeking an ideal existence for a very long time. In this existence, justice, love, and peace are no longer words, but actual experiences. How ever, with the American preemptive invasion and occupation of Afghanistan and Iraq and the subsequent prisoner abuse, such an existence seems to be farther and farther away from reality. The purpose of this work is to stop this dangerous trend by promoting justice, love, and peace through a change of the paradigm that is inconsistent with justice, love, and peace. The strong paradigm that created the strong nation like the U.S. and the strong man like George W. Bush have been the culprit, rather than the contributor, of the above three universal ideals. Thus, rather than justice, love, and peace, the strong paradigm resulted in in justice, hatred, and violence. In order to remove these three and related evils, what the world needs in the beginning of the third millenium is the weak paradigm. Through the acceptance of the latter paradigm, the golden mean or middle paradigm can be formulated, which is a synergy of the weak and the strong paradigm. In order to understand properly the meaning of these paradigms, however, some digression appears necessary.
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Dominique Gobin and Benoit Goyeau
This paper aims to provide a limited, but selective bibliography on modelling heat and mass transfer in composite fluid‐porous domains.
Abstract
Purpose
This paper aims to provide a limited, but selective bibliography on modelling heat and mass transfer in composite fluid‐porous domains.
Design/methodology/approach
Since the pioneer study by Beavers and Joseph, the problem of interface continuity and/or jump conditions at a fluid‐porous interface has been of interest to the fluid mechanics and heat and mass transfer community. The paper is concerned both with numerical simulations of heat and fluid flow in such systems, and with the linear stability problems.
Findings
The one‐ and two‐domain formulations are equivalent. Using the Darcy‐Brinkman extension instead of the Darcy model reduces the number of ad hoc parameters in this configuration.
Research limitations/implications
The problem of double diffusive convection has still to be solved and analyzed.
Practical implications
The discussion on the interface conditions is of great relevance to many industrial and practical situations.
Originality/value
The important question of the macroscopic formulation of the problem is tackled in the paper.
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A comparative study is made between different flow models for analysisof natural convection in a differentially heated vertical square cavityfilled with a fluid saturated porous…
Abstract
A comparative study is made between different flow models for analysis of natural convection in a differentially heated vertical square cavity filled with a fluid saturated porous medium. The solution is obtained by using a finite element method. The Darcy‐modified Rayleigh number, Ra*, is varied from 50 to 1000 while the Darcy number, Da, ranges from 5 × 10–7 to 10–2. It is generally observed that for small values of Ra* and Da, all other models converge with the Darcy flow model. However, for large values of Ra* and Da, the Darcy flow model predicts the highest heat transfer rate, and the Brinkman‐Forchheimer extension yields the lowest heat transfer rate whilst prediction from the Brinkman‐extended model lies in between.
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Nicola Massarotti, Michela Ciccolella, Gino Cortellessa and Alessandro Mauro
The purpose of this paper is to focus on the numerical analysis of transient free convection heat transfer in partially porous cylindrical domains. The authors analyze the…
Abstract
Purpose
The purpose of this paper is to focus on the numerical analysis of transient free convection heat transfer in partially porous cylindrical domains. The authors analyze the dependence of velocity and temperature fields on the geometry, by analyzing transient flow behavior for different values of cavity aspect ratio and radii ratio; both inner and outer radius are assumed variable in order to not change the difference ro-ri. Moreover, several Darcy numbers have been considered.
Design/methodology/approach
A dual time-stepping procedure based on the transient artificial compressibility version of the characteristic-based split algorithm has been adopted in order to solve the transient equations of the generalized model for heat and fluid flow through porous media. The present model has been validated against experimental data available in the scientific literature for two different problems, steady-state free convection in a porous annulus and transient natural convection in a porous cylinder, showing an excellent agreement.
Findings
For vertically divided half porous cavities, with Rayleigh numbers equal to 3.4×106 for the 4:1 cavity and 3.4×105 for the 8:1 cavity, the numerical results show that transient oscillations tend to disappear in presence of cylindrical geometry, differently from what happens for rectangular one. The magnitude of this phenomenon increases with radii ratio; the porous layer also affects the stability of velocity and temperature fields, as oscillations tend to decrease in presence of a porous matrix with lower value of the Darcy number.
Research limitations/implications
A proper analysis of partially porous annular cavities is fundamental for the correct estimation of Nusselt numbers, as the formulas provided for rectangular domains are not able to describe these problems.
Practical implications
The proposed model represents a useful tool for the study of transient natural convection problems in porous and partially porous cylindrical and annular cavities, typical of many engineering applications. Moreover, a fully explicit scheme reduces the computational costs and ensures flexibility.
Originality/value
This is the first time that a fully explicit finite element scheme is employed for the solution of transient natural convection in partially porous tall annular cavities.
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Presents the case for the use of computerised Bills of Lading. Outlines the issues of concern with electronic documents, showing that these documents have various roles to play…
Abstract
Presents the case for the use of computerised Bills of Lading. Outlines the issues of concern with electronic documents, showing that these documents have various roles to play, each of which must be considered when looking at the safeguards built into electronic systems. Considers Digital signatories, legal contractual agreements and various legislative approaches. Covers cross border jurisdiction and digital negotiability before looking at the European Model EDI Agreement. Comments on the Uncitral Model Law on Electronic Commerce and then presents the position held by the banking community. States the arguments for the paper form compared to the electronic form and concludes that there is a need for more understanding and legal clarification within the subject.
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HARROGATE will be notable as the venue of the Conference in one or two ways that distinctive. The Association Year is now to begin on January 1st and not in September as…
Abstract
HARROGATE will be notable as the venue of the Conference in one or two ways that distinctive. The Association Year is now to begin on January 1st and not in September as heretofore; and, in consequence, there will be no election of president or of new council until the end of the year. The Association's annual election is to take place in November, and the advantages of this arrangement must be apparent to everyone who considers the matter. Until now the nominations have been sent out at a time when members have been scattered to all parts of the country on holiday, and committees of the Council have been elected often without the full consideration that could be given in the more suitable winter time. In the circumstances, at Harrogate the Chair will still be occupied by Sir Henry Miers, who has won from all librarians and those interested in libraries a fuller measure of admiration, if that were possible, than he possessed before he undertook the presidency. There will be no presidential address in the ordinary sense, although Sir Henry Miers will make a speech in the nature of an address from the Chair at one of the meetings. What is usually understood by the presidential address will be an inaugural address which it is hoped will be given by Lord Irwin. The new arrangement must bring about a new state of affairs in regard to the inaugural addresses. We take it that in future there will be what will be called a presidential address at the Annual Meeting nine months after the President takes office. He will certainly then be in the position to review the facts of his year with some knowledge of events; he may chronicle as well as prophesy.
We have reprinted the powerful letter addressed to the Daily Mail by MR. H. W. WILSON, the author of “Ironclads in Action,” advocating the immediate adoption of a policy of…
Abstract
We have reprinted the powerful letter addressed to the Daily Mail by MR. H. W. WILSON, the author of “Ironclads in Action,” advocating the immediate adoption of a policy of reprisals for the Zeppelin murder raids. In our view it is the duty of every journal, whatever may be its raison d'être, to assist in keeping the attention of the public fixed upon this matter, to aid in preventing the general feeling of disgust and indignation from cooling down, and to support those who have the brains to understand the nature of the Hun in their efforts to compel the Government to adopt the most effective means at present available to put an end to the murderous excursions of the German vermin into this country. As MR. WILSON points out, the deliberate Hun policy of slaying women, children and non‐combatants is either permitted by the laws of war recognised by civilised nations or it is not permitted by those laws. If it is permitted, “then clearly the Power which refrains from making similar attacks on the enemy's towns, villages, and residential districts, loses greatly from the military standpoint.” If it is not permitted then the only course— “the force behind the laws of War”—is a policy of drastic reprisals. Moreover, it is the only course that the Hun can understand. The methods of “frightfulness” are definitely laid down in the German military system as methods to be ruthlessly followed whenever this can be done with impunity and the fear of reprisals is also definitely laid down as the only consideration which is to be allowed to operate as a check upn “frightfulness.” “The Power which fails to take reprisals when a great offence is committed is as the negligent judge or the faithless jury that acquits a murderer. It sins against humanity … it encourages the criminal in his crime.”
John Hamel, Sarah Desmarais, Tonia Nicholls, Kathleen Malley‐Morrison and Jon Aaronson
If child custody decisions are based on erroneous beliefs, family courts may not be acting in the best interests of children. This study examined family court professionals'…
Abstract
If child custody decisions are based on erroneous beliefs, family courts may not be acting in the best interests of children. This study examined family court professionals' beliefs about family violence. Respondents (N = 410) of diverse professions, including child custody mediators, evaluators, and therapists, family law attorneys and judges, victim advocates and university students, completed a 10‐item multiple‐choice quiz. Results revealed low rates of correct responding, with respondents correctly answering approximately three out of 10 items on average, based on current research in the field. Overall, response rates were highly consistent with the discredited patriarchal paradigm. Shelter workers and victim advocates had the lowest average score, and men were found to have slightly higher scores than women. More troubling, students' scores were not significantly lower than those of family court professionals. Implications are discussed with respect to decision‐making in the context of child custody disputes.